Conventional automobile spraybooths dry solvent-borne paints which have been applied onto the surfaces of a motor vehicle by passing heated air over the painted surface. Typically, heated air is blown into the spraybooth through inlets, e.g. in the booth ceiling, and is evacuated through floor outlets.
The surfaces of the bodies such as motor vehicles, and particularly non-conductive components such as plastic bumpers, are normally found to be electro-statically charged. This electrostatic charge results from normal handling of the body prior to painting and is generally unavoidable.
The electrostatically charged surfaces of the vehicle attract dirt and dust particles and this results in contamination of the painted surface.
In an attempt to reduce such contamination, the surface is typically degreased and “tacked off” (rubbed using what is commonly referred to as a “tack rag”) prior to painting. However, this can be counter-productive as the rubbing action greatly increases the static charge on the surface. Loose/airborne particles originating from tack cloths, operator clothing, etc., are then attracted to the surface.
Paint is typically applied to motor vehicles using a spray gun. When the paint is atomized from the spray gun, this also acquires a static charge which attracts dirt and dust particles.
The result is that the painted surface is often contaminated by dust/dirt particles and, although the painting process is designed for a “gun finish” without subsequent polishing, refinishing work is often necessary involving many wasted hours of removing dirt ingressed during painting which reduces the cost effectiveness of the painting operation.
A further problem is that metallic paint finishes make up approximately 50% of car colors currently on the road. Mica or aluminum is used to produce the metallic finish and is disturbed by static charge which can result in a patchy surface and color inaccuracy.